1. Field of the Invention
The present invention relates in general to the field of microelectronic device verification, and more specifically to a method and system for entropy driven verification of a microelectronic device design.
2. Description of the Related Art
Microelectronic device designs typically undergo a rigorous verification process before general commercial release. Initial high-level designs specify circuits to perform designed functions, such as generating a predetermined output for a given input. Automated tools then generally take the high-level designs to create a low-level design, such as with gates and transistors fabricated in a semiconductor material. Upon completion of the low-level design, the microelectronic device design is then typically verified with computer simulations and with hardware implementations of the microelectronic device design as an integrated circuit. In the computer simulation environment, predetermined stimulus is applied to a computer model of the low-level design and the simulated output generated by the stimulus is examined to determine that the microelectronic device design performs the designed function, such as by outputting an expected response to the stimulus. In a hardware verification, electrical signal stimuli are input into an integrated circuit having the microelectronic device design and the output response is compared with an expected response to verify that the integrated circuit operates as designed.
Verification of microelectronic device designs is often a complex and time-consuming process. Integrated circuits have grown increasingly complex and typically have millions of transistors that perform a myriad of functions. Complete design specification and complete verification are often not practical, particularly with complex integrated circuits and tight commercial release dates. Instead, verification generally relies on directed stimuli generated to verify selected functions and random stimuli over a limited duration generated to verify as much of the design state space as practical. Random generation typically uses weights that affect the values of randomly generated stimuli and allows some directed coverage of desired design state space. A combination of directed and random verification testing along with the design state space covered by the verification testing allows an estimation of the stability of the microelectronic device design. Stability determinations generally grow more accurate as the time for application of random stimuli increases; however, even extensive random verification cannot guarantee the status of a microelectronic device design.